Search results
Results From The WOW.Com Content Network
Another factor is due to the shortage of food stocks during winter as the insects are being driven away and as the result, bat hibernate in pregnant condition. [24] In pinnipeds, the purpose of delayed implantation is in order to increase survival chance of the young animals as the mother ensure that the neonates are born at an optimal season. [25]
At other times of the year, they will be anestrus, or have a dearth of their sexual cycle. Unlike reproductive cyclicity, seasonality is described in both males and females. [citation needed] Male seasonal breeders may exhibit changes in testosterone levels, testes weight, and fertility depending on the time of year. [2]
Human pregnancy can be divided into three trimesters, each approximately three months long: the first, second, and third trimester. The first trimester is from the last menstrual period through the 13th week, the second trimester is 14th–28/29th week, and the third trimester is 29/30th–42nd week. [ 6 ]
Other than the few bulls needed for breeding, the vast majority of male cattle are castrated as calves and are used as oxen or slaughtered for meat before the age of three years. Thus, in a pastured herd, any calves or herd bulls usually are clearly distinguishable from the cows due to distinctively different sizes and clear anatomical differences.
Mouthing a two tooth grass-fed Murray Grey heifer prior to sale. The age of cattle is determined chiefly by examination of the teeth, and less perfectly by the horn rings or the length of the tail brush; due to bang-tailing, which is the act of cutting the long hairs at the tip of the tail short to identify the animal after management practices, the last method is the least reliable.
This is a list of some of the cattle breeds considered in the United States to be wholly or partly of American origin. Some may have complex or obscure histories, so inclusion here does not necessarily imply that a breed is predominantly or exclusively American.
Polled strains have been developed of many cattle breeds which were originally horned. This has usually been done by crossing with naturally polled breeds, most commonly Angus and Galloway cattle. For example, polled Jersey cattle originated in Ohio sometime prior to 1895. Two strains were developed, the first to appear being founded by crosses ...
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus , and ends once it leaves the uterus.